Bicycle rear suspension

ABSTRACT

A bicycle comprises a front wheel; a rear wheel; a frame comprising a main frame portion and an articulating frame portion, the articulating frame portion comprising: a lower arm pivotally supported at a first axis by the main frame portion; an upper frame link pivotally supported at a second axis by the main frame portion; an upper arm pivotally coupled to the upper frame link at a third axis; an upper shock link pivotally coupled to the upper frame link and the upper arm at the third axis; and a lower shock link pivotally coupled to the main frame portion and the lower arm at the first axis; and a shock absorber having a first end pivotally supported at a fourth axis by the main frame portion, and a second end pivotally supported at a fifth axis by the upper shock link and the lower shock link.

TECHNICAL FIELD

The present technology relates generally to vehicle suspension systems.More particularly, the present technology relates to a rear wheelsuspension assembly suitable for use in connection with off-roadbicycles.

DESCRIPTION OF THE RELATED TECHNOLOGY

Off-road bicycles, or mountain bikes, may be equipped with front andrear suspension assemblies operably positioned between the front andrear wheels, respectively, and the frame of the bicycle. Providing frontand rear suspension on a mountain bike potentially improves handling andperformance by absorbing bumps, and other rough trail conditions, whichmay be encountered while riding off-road. As the sport of mountainbiking has evolved, the size and difficulty of the obstacles that havebecome commonplace has increased in scale. As a result, bicyclemanufacturers have attempted to continually increase the amount ofsuspension travel and/or performance of the suspension systems toaccommodate more aggressive riding. Such designs can present a varietyof problems, however, such as increased weight and/or less desirableperformance near the end of the suspension travel.

One common bicycle rear suspension design involves a single lever, orswingarm, supporting a rear wheel at one end and being pivotallyconnected to the bicycle frame at the other end. Although such a systemis simple and reliable, the single lever, or single pivot, rearsuspension design suffers from a relatively large amount of pedal forcesand braking forces being transmitted into the rear suspension assembly.

Rear suspension designs that include multiple lever members and,therefore, multiple pivots, typically exhibit better isolation ofpedaling forces and braking forces from the rear suspension. Typically,a multiple lever rear suspension assembly will have a pair of lower arms(i.e., chain stays) pivotally connected to the bicycle frame at aforward end and a link member pivotally mounted to the main frame at alocation above the chain stays. A pair of rearward arms (i.e., seatstays) are pivotally connected between rearward ends of the chain staysand link member. The rear wheel may be carried by either of the chainstays or seat stays. Typically, the rear shock absorber is operablypositioned between the link member and the main frame. As a result,placement of the shock absorber is at a relatively high position withinthe bicycle frame, thereby raising the overall center of gravity of thebicycle, which is detrimental to the handling qualities of the bicycle.This drawback is magnified in large suspension travel designs, whereinthe size of the rear shock absorber is typically increased. Anotherpotential drawback of large suspension travel designs is that the rearwheel will tend to travel along a forward arc-shaped path as thesuspension is compressed, with the forward arc being more pronouncednear the end of the stroke.

SUMMARY

The systems, methods, and devices described herein have innovativeaspects, no single one of which is indispensable or solely responsiblefor their desirable attributes. Without limiting the scope of theclaims, some of the advantageous features will now be summarized.

The present disclosure describes bicycles having rear bicycle suspensionsystems that address one or more of the deficiencies described above andthat provide one or more of a variety of benefits over previous rearsuspension systems, such as a rear axle that can follow a more verticalpath, especially near the end of stroke, lower weight, easiermanufacturability, a lower center of gravity that can help to improvehandling, and a more progressive shock leverage ratio, such as to avoidharsh bottoming out of the suspension.

According to some embodiments, a bicycle comprises: a front wheel; arear wheel; a frame comprising a main frame portion and an articulatingframe portion, said articulating frame portion carrying said rear wheel,said articulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame link ata third axis; an upper shock link pivotally coupled to the upper framelink and the upper arm at the third axis; and a lower shock linkpivotally coupled to the main frame portion and the lower arm at thefirst axis; and a shock absorber having a first end and a second end,the first end pivotally supported at a fourth axis by the main frameportion, the second end pivotally supported at a fifth axis by the uppershock link and the lower shock link, the shock absorber configured tobias the articulating frame portion to the relaxed configuration.

In some embodiments, the fourth axis is collinear with the second axis.In some embodiments, the upper and lower shock links are positioned suchthat the first axis, third axis, and fifth axis are never coplanarthroughout a range of motion of the articulating frame portion from therelaxed configuration to the compressed configuration. In someembodiments, the fourth axis is positioned above the fifth axis suchthat a longitudinal axis of the shock absorber slopes downward from thefirst end to the second end in all positions between the compressedconfiguration and the relaxed configuration. In some embodiments, thefourth axis and the fifth axis are both positioned below the second axisthroughout a range of motion of the articulating frame portion from therelaxed configuration to the compressed configuration.

According to some embodiments, a bicycle comprises: a front wheel; arear wheel; a frame comprising a main frame portion and an articulatingframe portion, said articulating frame portion carrying said rear wheel,said articulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame linkand the lower arm; an upper shock link pivotally supported at a thirdaxis by one or both of the upper frame link and the upper arm; and alower shock link pivotally coupled to the main frame portion; a shockabsorber having a first end and a second end, the first end pivotallysupported at a fourth axis by the main frame portion, the second endpivotally supported at a fifth axis by the upper shock link and thelower shock link, the shock absorber configured to bias the articulatingframe portion to the relaxed configuration; and a pedal crank rotatablycoupled to the main frame portion at sixth axis, the first axis beingforward of the sixth axis; wherein, when the bicycle is positioned on ahorizontal surface with the articulating frame portion in the relaxedconfiguration, a horizontal distance from the sixth axis to the firstaxis is at least 1.5 inches.

In some embodiments, when the bicycle is positioned on a horizontalsurface with the articulating frame portion in the relaxedconfiguration, the horizontal distance from the sixth axis to the firstaxis is at least 3 inches. In some embodiments, when the bicycle ispositioned on a horizontal surface with the articulating frame portionin the relaxed configuration, a horizontal distance from a rotationalaxis of the rear wheel to the first axis is no greater than 10 times thehorizontal distance from the sixth axis to the first axis. In someembodiments, when the bicycle is positioned on a horizontal surface withthe articulating frame portion in the relaxed configuration, ahorizontal distance from a rotational axis of the rear wheel to thefirst axis is no greater than 7 times the horizontal distance from thesixth axis to the first axis. In some embodiments, when the articulatingframe portion is in the relaxed configuration, a horizontal distancefrom a rotational axis of the rear wheel to the first axis is at least18 inches. In some embodiments, when the articulating frame portion isin the relaxed configuration, a horizontal distance from the rotationalaxis of the rear wheel to the first axis is at least 20 inches.

According to some embodiments, a bicycle comprises: a front wheel; arear wheel; a frame comprising a main frame portion and an articulatingframe portion, said articulating frame portion carrying said rear wheel,said articulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame linkand the lower arm; an upper shock link pivotally supported at a thirdaxis by one or both of the upper frame link and the upper arm; and alower shock link pivotally coupled to the main frame portion; and ashock absorber having a first end and a second end, the first endpivotally supported at a fourth axis by the main frame portion, thesecond end pivotally supported at a fifth axis by the upper shock linkand the lower shock link, the shock absorber configured to bias thearticulating frame portion to the relaxed configuration; wherein thefirst axis is positioned forward of the second axis when the bicycle ispositioned on a horizontal surface with the articulating frame portionin the relaxed configuration.

In some embodiments, the first axis is positioned at least 0.50 inchesforward of the second axis when the bicycle is positioned on ahorizontal surface with the articulating frame portion in the relaxedconfiguration. In some embodiments, the upper shock link is pivotallysupported at the third axis by both of the upper frame link and theupper arm. In some embodiments, the rear wheel is rotatably coupled tothe upper arm. In some embodiments, the lower shock link is pivotallycoupled to the main frame portion at a sixth axis, and the upper andlower shock links are positioned such that the third axis, fifth axis,and sixth axis are never coplanar throughout a range of motion of thearticulating frame portion from the relaxed configuration to thecompressed configuration. In some embodiments, the sixth axis iscollinear with the first axis. In some embodiments, the second axis iscollinear with the fourth axis. In some embodiments, the fourth axis ispositioned above the fifth axis such that a longitudinal axis of theshock absorber slopes downward from the first end to the second end inall positions between the compressed configuration and the relaxedconfiguration. In some embodiments, the fourth axis is positioned belowthe second axis. In some embodiments, the fourth axis and the fifth axisare both positioned below the second axis throughout a range of motionof the articulating frame portion from the relaxed configuration to thecompressed configuration. In some embodiments, the second end of theshock absorber comprises a shock extension pivotally supported at thefifth axis by the upper shock link and the lower shock link.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects, as well as other features, aspects, andadvantages of the present technology will now be described in connectionwith various embodiments, with reference to the accompanying drawings.The illustrated embodiments, however, are merely examples and are notintended to be limiting.

FIG. 1 is a side elevational view of an off-road bicycle, or mountainbike, incorporating a bicycle frame having certain features, aspects andadvantages of the present technology.

FIG. 2 is a side elevational view of the bicycle frame of FIG. 1 withcertain components of the bicycle removed for the purpose of clarity.

FIG. 3 is a side elevational view of the bicycle frame of FIG. 2 withadditional components removed for the purpose of clarity.

FIG. 4 is a perspective view showing the top, right, and rear sides ofthe bicycle frame of FIG. 2.

FIG. 5 is a rear elevational view of the bicycle frame of FIG. 2.

FIGS. 6A-6D are side elevational views of alternative embodiments ofbicycle frames.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part of the present disclosure. Theillustrative embodiments described in the detailed description,drawings, and claims are not meant to be limiting. Other embodiments maybe utilized, and other changes may be made, without departing from thespirit or scope of the subject matter presented here. It will be readilyunderstood that the aspects of the present disclosure, as generallydescribed herein, and illustrated in the figures, can be arranged,substituted, combined, and designed in a wide variety of differentconfigurations, all of which are explicitly contemplated and form partof this disclosure. For example, a system or device may be implementedor a method may be practiced using any number of the aspects set forthherein. In addition, such a system or device may be implemented or sucha method may be practiced using other structure, functionality, orstructure and functionality in addition to or other than one or more ofthe aspects set forth herein. Alterations and further modifications ofthe inventive features illustrated herein, and additional applicationsof the principles of the inventions as illustrated herein, which wouldoccur to one skilled in the relevant art and having possession of thisdisclosure, are to be considered within the scope of the invention.Descriptions of unnecessary parts or elements may be omitted for clarityand conciseness, and like reference numerals refer to like elementsthroughout.

The disclosure herein presents embodiments of improved bicycle rearsuspension systems having various benefits over prior art designs. Theembodiments described below may include one or more of the followingbenefits, among others: a rear axle path that follows more of a verticalpath instead of a forward arc, allowing for better absorption of bumps;a lower center of gravity, to enable better handling of the bicycle; amore progressive leverage ratio, to avoid harsh bottoming out of thesuspension system; reduced weight; and increased manufacturabilityand/or reduced manufacturing costs.

FIG. 1 illustrates one embodiment of an off-road bicycle, or mountainbike 10, including a preferred rear suspension assembly. The bicycle 10is described herein with reference to a coordinate system wherein alongitudinal axis extends from a forward end to a rearward end of thebicycle 10. A vertical, central plane generally bisects the bicycle 10and contains the longitudinal axis. A lateral axis extends normal to thelongitudinal axis and lies within a horizontal plane. In addition,relative heights are generally expressed as elevations from a horizontalsurface S upon which the bicycle 10 is supported in an upright position.Similarly, relative forward and rearward positions are expressed asdistances from a vertical axis, which is normal to the horizontalsurface S. The above-described coordinate system is provided for theconvenience of describing the embodiment illustrated in the figures, andis not intended to limit the scope of the present disclosure unlessexpressly indicated.

The bicycle 10 includes a frame assembly 12 comprised of a main frame 14and an articulating frame, or subframe 16, pivotally supported relativeto the main frame 14. The bicycle 10 also includes a front wheel 18carried by a front suspension assembly, or suspension fork 20. A steerertube (not shown) is journaled for rotation about a steering axis A_(S)defined by the main frame 14 (shown in FIG. 2). A handlebar assembly 22is connected to an upper end of the suspension fork 20 and is operableto permit a rider of the bicycle 10 to rotate the front wheel 18 aboutthe steering axis A_(S).

A rear wheel 24 of the bicycle 10 is carried by the subframe 16. A shockabsorber 26 is pivotally connected to both the main frame 14 and thesubframe 16 to provide resistance to articulating motion of the subframe16 relative to the main frame 14 and, thus, provide resistance to thesuspension travel of the rear wheel 24. The shock absorber 26 preferablybiases the subframe 16 to the relaxed configuration, as shown in FIG. 2.Returning to FIG. 1, a seat assembly 28 is supported above the bicycleframe 12 at a position behind the handlebar assembly 22 and providessupport for a rider of the bicycle 10.

A pedal crank assembly 32 is rotatably supported by the bicycle frame 12and drives a multi-speed chain drive arrangement 34. The bicycle 10 alsoincludes front and rear brake systems 36, 38 for slowing and stoppingthe bicycle 10. Although the illustrated brakes 36, 38 are disc-typebrakes, other suitable brake systems may also be used, such as rim-typebrakes for example. Rider controls (not shown) are typically provided onthe handlebar assembly 22 and are operable to control shifting of themulti-speed chain drive arrangement 34 and front and rear brake systems36, 38.

FIG. 2 illustrates the bicycle frame 12 and rear shock absorber 26 withthe remaining components of the bicycle 10 removed for clarity. FIG. 3illustrates the rear shock absorber 26 and a portion of the bicycleframe 12 (a shock support assembly 80 and a lever arm 74), with theremaining components of the bicycle frame 12 removed for clarity. FIGS.4 and 5 illustrate additional views of the bicycle frame 12, with therear shock absorber 26 also removed for clarity. As described above,preferably, the bicycle frame 12 is primarily comprised of a main frame14 and an articulating frame, or subframe 16. The main frame 14 includesa head tube 50 which defines the steering axis A_(S) of the bicycleframe 12. Desirably, the steering axis A_(S) is canted rearwardly from avertical axis. The head tube 50 is configured to rotatably support thefront suspension 20 and, thus, the front wheel 18 of the bicycle 10.

A top tube 52 and a down tube 54 extend in a rearward direction from thehead tube 50 and diverge from one another when moving toward theirrearward ends. A bottom bracket support member 56 extends between therearward ends of the top tube 52 and the down tube 54 and togethertherewith defines a shape that may be generally triangular or may takeother forms. The bottom bracket support member 56 includes a bottombracket shell 58, which supports the pedal crank assembly 32 (shown inFIG. 1) for rotation about a crank axis A_(C).

A seat tube 60 extends in an upward direction from a rearward end of thetop tube 52 and, preferably, is canted rearwardly from a vertical axis.The seat tube 60 supports the seat assembly 28 shown in FIG. 1.Desirably, a gusset 62 extends from a forward side of the seat tube 60to an upper side of the top tube 52 to provide additional strength tothe seat tube 60.

Preferably, the main frame 14 is constructed of individual components,as described above, which are fabricated from a metal material, such asaluminum or steel, and welded together. Desirably, the bottom bracketsupport member 56 is created from a metal material by a forging processand, thus, benefits from the strength and durability advantages thatinherently result from the forging process. Preferably, the articulatingframe 16 is directly supported by the bottom bracket support member 56,as is described in greater detail below. Further, the shock absorber 26is preferably supported by a bracket 57 attached to the down tube 54. Insome embodiments, the bracket 57 may be connected to and/or be formed asa part of the bottom bracket support member 56. In some embodiments, atleast a portion of the bracket 57 may be connected to the bottom bracketsupport member 56 by a gusset. For example, as shown in FIG. 2, a gusset58 desirably extends from a forward side of the bottom bracket supportmember 56 to an upper or rearward side of the bracket 57.

However, in alternative embodiments, the main frame 14 may beconstructed in a more conventional fashion wherein the forged bottombracket support member 56, bracket 57, and/or gusset 58 are omitted andthe articulating frame 16 and shock absorber 26 may be pivotallyconnected to the welded-up tubes comprising the main frame 14. Further,other suitable constructions of the main frame 14, includingnon-triangular constructions, may also be used, such as a monocoqueconstruction, for example. In addition, alternative materials such ascomposites may also be used in whole or in part to construct the mainframe 14, as will readily be appreciated by one of skill in the art. Theillustrated embodiment is preferred, however, for at least the reasonsdiscussed herein.

As described above, the illustrated bicycle frame 10 includes a shockabsorber 26 operably positioned between the main frame 14 and thesubframe 16. Desirably, the shock absorber 26 is configured to provideboth a spring force and a damping force in response to relative movementbetween the subframe 16 and the main frame 14, as is known in the art.The spring force is related to the relative position between thesubframe 16 and the main frame 14 while the damping force is related tothe relative speed of movement between the subframe 16 and the mainframe 14.

Although the illustrated shock absorber 26 comprises an air spring typeshock absorber, other suitable suspension shock absorbers, such as thoseincorporating a coil type spring, for example, may also be used.Preferably, the damping system comprises a piston movable within a fluidcylinder of the shock absorber 26. Desirably, the piston forceshydraulic fluid within the fluid chamber through one or more restrictiveflow paths to generate a damping force when the shock absorber 26 isboth extending and compressing, as is known in the art. In addition,other types of damping arrangements, such as inertia activated andposition sensitive arrangements, may also be used, as will be readilyunderstood by one of skilled in the art.

As described above, the subframe 16 is configured to support the rearwheel 24 (as shown in FIG. 1) for a movement throughout a suspensiontravel path relative to the main frame 14 from a relaxed position,substantially as illustrated in FIG. 2, to a compressed position,wherein the subframe 16 is pivoted in an upward direction relative tothe main frame 14. Preferably, the subframe 16 is a multiple linkageassembly. That is, preferably, the subframe 16 includes a plurality oflinkage members pivotally interconnected with one another. However, inalternative arrangements, a single link member may carry the rear wheel24 for movement in a simple, arcuate suspension travel path relative tothe main frame 14.

In the illustrated arrangement, the subframe 16 includes a chain staymember 70 having a forward end 70 a pivotally connected to the mainframe 14 for rotation about a pivot axis 72 a. Preferably, the chainstay member 70 includes a pair of laterally-spaced arms that extend in arearward direction from the forward end 70 a and straddle the rear wheel24 (as shown in FIG. 1). However, in an alternative arrangement, thechain stay member 70 may comprise a single arm positioned on one side ofthe rear wheel 24. Desirably, the chain stay member 70 is connecteddirectly to the main frame 14. However, alternatively, the chain staymember 70 may be connected to the main frame 14 indirectly, such asthrough an additional link member, for example.

A link member, or lever arm 74, is pivotally connected at a forward end74 a to the main frame 14 for a pivotal motion about a pivot axis 72 b.Desirably, the pivot axis 72 b is spaced above the pivot axis 72 a and,preferably, is positioned proximate a junction between the seat tube 60and the top tube 52. In the illustrated embodiment, the forward end 74 aof the link member 74 includes a pair of arm portions straddling theseat tube 60.

A seat stay member 76 is pivotally supported at an upper end 76 a by arearward end 74 b of the link member 74 for pivotal movement about apivot axis 72 c. A lower end 76 b of the seat stay member 76 ispivotally supported at a pivot axis 72 d defined by a rearward end 70 bof the chain stay member 70. Preferably, the seat stay member 76includes a pair of laterally-spaced arms straddling the rear wheel 24(as shown in FIG. 1) and interconnected by a bridge 78 at the upper end76 a of the seat stay member 76.

Desirably, a first or front end 26 a of the shock absorber 26 ispivotally connected to the main frame 14 and, more specifically, to thebracket 57 coupled to the down tube 54 for rotation about a pivot axis75 a. The bracket 57 may be connected to or formed as part of the bottombracket support member 56, which may be desirable, for example, toincrease rigidity between pivot axes 75 a, 72 a, and 72 b. In someembodiments, however, the bracket 57 is not connected to or formed as apart of the bottom bracket support member 56. Further, a gusset 58 maydesirably provide additional structural rigidity to the pivot axis 75 aby connecting a portion of the bracket 57 adjacent the pivot axis 75 ato an upper end of the bottom bracket support member 56. A second orrearward end 26 b of the shock absorber is pivotally connected to ashock support assembly 80 at pivot axis 75 b. The shock support assembly80 preferably comprises an upper shock link 82 having a first end 82 aand a second end 82 b, and a lower shock link 84 having a first end 84 aand a second end 84 b. The second end 82 b of the upper shock link 82 ispreferably pivotally coupled to the second end 84 b of the lower shocklink 84 at pivot axis 75 b. The first end 82 a of the upper shock link82 is preferably pivotally coupled to the link member 74 and seat stayor upper arm 76 at pivot axis 72 c. The first end 84 a of the lowershock link 84 is preferably pivotally coupled to the chain stay or lowerarm 70 and the bottom bracket support member 56 at pivot axis 72 a.

Although this embodiment shows the shock support assembly 80 havingthree pivot axes 72 a, 75 b, and 72 c each having at least three memberscoupled for rotation thereabout, other embodiments may utilize differentarrangements. For example, the first end 82 a of the upper shock link 82may be pivotally coupled only to the link member 74 or only to the seatstay 76 at a pivot axis different than axis 72 c. One example of such anembodiment is shown in FIG. 6B. FIG. 6B illustrates an assemblycomprising a frame 12 and shock absorber 26 that is similar to theembodiment illustrated in FIG. 2, except for the first end 82 a of theupper shock link 82 being pivotally coupled to the link member 74 atpivot axis 72 e. In another alternative embodiment, pivot axis 72 e maybe positioned on the seat stay 76, instead of the link member 74.

As another example, the first end 84 a of the lower shock link 84 may bepivotally coupled to the lower arm 70 or the main frame 14 at a pivotaxis different than pivot axis 72 a. One example of such an embodimentis shown in FIG. 6C. FIG. 6C illustrates an assembly similar to theembodiment illustrated in FIG. 2, except for the first end 84 a of thelower shock link 84 being pivotally coupled to the bottom bracketsupport member 56 at pivot axis 72 e instead of pivot axis 72 a. Aportion of the lower arm 70 is hidden in FIG. 6C for clarity.

As another example, the front end 26 a of the shock absorber 26 may bepivotally supported at a pivot axis shared by one or more other members.One example of such an embodiment is shown in FIG. 6A. FIG. 6Aillustrates an assembly similar to the embodiment illustrated in FIG. 2,except for the front end 26 a of the shock absorber 26 being pivotallycoupled to the bottom bracket support member 56 and link member 74 atpivot axis 72 b. Further, the embodiment of FIG. 6A desirably no longerincludes the bracket 57 or gusset 58 (see FIG. 2), because the shockabsorber 26 is no longer pivotally coupled to the down tube 54.

As further described below, it can be beneficial to utilize a designthat comprises one or more pivot axes that have more than two memberscoupled thereto. Stated another way, it can be beneficial to have one ormore pivot axes that is shared by at least three members.

Returning to FIGS. 1-5, advantageously, the illustrated shock supportassembly 80 positions the rearward end 26 b of the shock absorber 26 ata relative position configured to accommodate the rear wheel 24 withoutrequiring an increase in the overall length of the frame. Preferably,the pivot axis 75 b of the rearward end 26 a of the shock absorber 26 isspaced from the rear hub axis A_(H) a radial distance of at least about26 inches in order to accommodate a rear wheel 24 of a typical diameter.However, the positioning of the pivot axis 75 b may also be configuredto accept larger wheels.

In one typical prior art arrangement, a shock absorber is situated in asubstantially vertical orientation in front of a seat tube. However, inthe presently illustrated arrangement, the rearward end 26 b of theshock absorber is positioned relatively lower than the forward end 26 aof the shock absorber, with the forward end 26 a being positioned belowthe seat tube 60. Furthermore, the rearward end 26 b of the shockabsorber 26 is supported by the shock support assembly 80 at a positionbelow the link member 74. Thus, the shock absorber 26 is mounted at asignificantly lower position within the bicycle frame 12 than in theprior art arrangements. Accordingly, the illustrated arrangementprovides a significantly lower center of gravity of the bicycle frame 12than prior art arrangements, which improves handling characteristics ofthe associated bicycle 10. Preferably, in the relaxed configuration(shown in FIG. 2), pivot axis 75 b is positioned at least 5 inches belowpivot axis 72 b. In some embodiments, in the relaxed configuration,pivot axis 75 b is positioned 3-8, 4-7, or 5-6 inches below pivot axis72 b. Preferably, pivot axis 75 a is positioned at least 2 inches belowpivot axis 72 b. In some embodiments, pivot axis 75 a is positioned 0-5,1-4, or 1.5-3 inches below pivot axis 72 b.

As described above, the rearward end 26 b of the shock absorber 26 ispositioned relatively lower than the forward end 26 a. Thus, the pivotaxis 75 b is positioned relatively lower than the pivot axis 75 a. Thus,a longitudinal axis of the shock absorber 26 is canted in a downwarddirection when moving from the forward end 26 a toward the rearward end26 b of the shock absorber 26. In addition, preferably, the pivot axis75 a and the pivot axis 75 b straddle the crank axis A_(C). That is, theforward end 26 a and forward pivot axis 75 a of the shock absorber 26are positioned forward of the crank axis A_(C) while the rearward end 26b and rearward pivot axis 75 b of the shock absorber 26 are positionedrearward of the crank axis A_(C). Preferably, the forward pivot axis 75a of the shock absorber 26 is positioned between about 4 and 12 inchesforward of the crank axis A_(C) and, more preferably, between about 5and 7 inches forward of the crank axis A_(C). Preferably, the rearwardpivot axis 75 b of the shock absorber 26 is positioned, in the relaxedconfiguration shown in FIG. 2, between about 1 and 3 inches rearward ofthe crank axis A_(C).

Accordingly, with such a construction, a relatively long shock absorber26 may be accommodated in a relatively low position without resulting ina lengthening of the bicycle frame 12. In a long travel bicycle frame,it is desirable to provide a shock absorber of a relatively increasedlength in order to retain a desirable ratio between movement of the rearwheel and corresponding movement (i.e., compression or rebound movement)of the shock absorber. If the ratio of wheel movement to shock absorbermovement is increased, the force transmitted to the shock absorber isincreased, which may be offset by higher spring and damping rates of theshock absorber. The higher spring and damping rates result in areduction in the ride characteristics of the shock absorber, however.Thus, the illustrated rear suspension assembly is capable ofaccommodating a suitably-sized shock absorber 26 in order to maintain adesirable ratio between movement of the rear wheel 24 and movement ofthe shock absorber 26.

One benefit of the design illustrated in FIGS. 1-5 is that the rear axlepath through the suspension travel can be more vertical and less of aforward arc than prior art designs. Many prior art designs for rearsuspension systems cause the rear axle path to follow a forward arcingcurve, with the forward arc being most pronounced at the end of thetravel. The designs disclosed herein, however, can allow the rear axlepath (i.e. the path of hub axis A_(H)) to remain more vertical,especially at the end of the stroke. This can improve bump absorption,because the wheel will tend to move more in the direction that bumps areencountered.

One feature of the designs disclosed herein that enables the rear wheelaxle path to remain more vertical (or to follow an at least partiallycurved or arc-shaped path having a larger radius than prior art designs)is that the pivot axis 72 a about which the chain stay or lower arm 70pivots is desirably positioned in front of the crank axis A_(C). Bypositioning the pivot axis 72 a in front of the crank axis A_(C), alonger distance between the pivot axis 72 a and the hub axis A_(H) andpivot axis 72 d can be achieved. Further, in some embodiments, the pivotaxis 72 a is the forward-most pivot axis of the subframe 16, meaningpivot axis 72 a is positioned forward of pivot axes 72 b, 72 c, and 72d. In this embodiment, the forward pivot axis 75 a of the shock absorber26 is positioned forward of the pivot axis 72 a; however, in otherembodiments, even the forward pivot axis of the shock absorber 26 may bepositioned rearward of the pivot axis 72 a (such as is shown in FIG.6A). In the present embodiment, the pivot axis 72 a is positionedapproximately 0.63 inches forward of the pivot axis 72 b, which is thenearest pivot axis in a horizontal direction. Desirably, the pivot axis72 a can be positioned at least 0.10, 0.25, 0.50, 0.75, 1.00, 1.25,1.50, 1.75, or 2.00 inches forward of the pivot axis 72 b. In someembodiments, the pivot axis 72 a is positioned 0.00-2.00, 0.10-1.50, or0.25-1.00 inches forward of the pivot axis 72 b. In some embodiments,however, the pivot axis 72 b may be in line with the pivot axis 72 b (ina horizontal direction), or may be behind the pivot axis 72 b.

Desirably, the pivot axis 72 a is positioned at least 3 inches forwardof the crank axis A_(C). In some embodiments, the pivot axis 72 a ispositioned at least 1, 1.5, 2, 2.5, 3.5, 4, 4.5, or 5 inches forward ofthe crank axis A_(C). In some embodiments, the pivot axis 72 a ispositioned 1-5 or 2-4 inches forward of the crank axis A_(C). Desirably,a horizontal distance between the pivot axis 72 a and the hub axis A_(H)is at least 18 inches when the subframe 16 is in the relaxedconfiguration. In some embodiments, the horizontal distance between thepivot axis 72 a and the hub axis A_(H) is at least 20 inches when thesubframe 16 is in the relaxed configuration. In some embodiments, thehorizontal distance between the pivot axis 72 a and the hub axis A_(H)is within a range of 17-23, 18-22, or 19-21 inches when the subframe 16is in the relaxed configuration. A ratio can also be used to describe arelative difference between (1) the horizontal distance between thecrank axis A_(C) and the pivot axis 72 a and (2) the horizontal distancebetween the hub axis A_(H) and the pivot axis 72 a. For example, in someembodiments, the horizontal distance from the hub axis A_(H) to thepivot axis 72 a is no greater than 10 times the horizontal distance fromthe crank axis A_(C) to the pivot axis 72 a when the subframe 16 is inthe relaxed configuration. In some embodiments, the horizontal distancefrom the hub axis A_(H) to the pivot axis 72 a is no greater than five,six, seven, eight, or nine times the horizontal distance from the crankaxis A_(C) to a pivot axis 72 a when the subframe 16 is in the relaxedconfiguration. In some embodiments, the horizontal distance from the hubaxis A_(H) to the pivot axis 72 a is within a range of 5-8 or 6-9 timesthe horizontal distance from the crank axis A_(C) to a pivot axis 72 awhen the subframe 16 is in the relaxed configuration.

Another benefit of the designs disclosed herein is that the linkagearrangement of the subframe 16 can enable a more progressive leverageratio than prior art designs. As of the subframe 16 is compressed ormoves from the relaxed configuration to the compressed configuration,the pivot axis 72 c will be caused to move up and forward. This willcause the upper shock link 82 and its pivot connection 75 b with shockabsorber 26 to also move up and forward. As this occurs, however, thefirst end or upper end 82 a of the upper shock link 82 will move forwardless than the second or lower end 82 b of the shock link 82 (rotatingthe upper shock link 82 in a counterclockwise direction as viewed inFIG. 2). Stated another way, an angle between two lines drawn throughthe pivot axes of the upper and lower shock links 82, 84 (shown as angleA in FIG. 3) will tend to increase as the suspension in compressed. Onereason for this is because the distance between pivot axes 72 c and 72 bis desirably longer than the distance between pivot axes 75 b and 72 a.Such a configuration will tend to decrease the leverage provided by theshock support assembly 80 as the suspension is compressed. Accordingly,as the suspension nears the end of its travel, the suspension willeffectively become progressively stiffer, reducing the likelihood of aharsh bottoming out. Desirably, the lengths and positioning of the uppershock link 82 and lower shock link 84 are configured such that the threecorresponding pivot axes 72 c, 75 b, and 72 a are never coplanarthroughout the suspension travel from the relaxed configuration to thecompressed configuration. Stated another way, if a line is drawn normalto and between pivot axes 72 a and 72 c, it is desirable for pivot axis75 b to always remain rearward of that line throughout the stroke of thesuspension travel. In some embodiments, the compressed configuration isdefined as a configuration in which the suspension assembly iscompressed to a point that one or more stop surfaces are engaged, thatmechanically resist further compression of the suspension assembly. Suchstop surfaces may be part of the shock absorber 26 and/or the subframe16. In some embodiments, the pivot axes 72 c, 75 b, and 72 a may beconfigured to become coplanar at or near the end of the stroke of thesuspension travel.

Another benefit of the designs disclosed herein relates to the sharingof pivot axes. For example, in the embodiment illustrated in FIGS. 1-5,the subframe 16 and shock absorber 26 assembly comprise a total of sixpivot axes, with three of those six pivot axes being shared by more thantwo members. Specifically, in this embodiment, pivot axis 72 a is sharedby three members (the main frame 14, the lower arm 70, and the lowershock link 84), pivot axis 72 c is shared by three members (link member74, upper arm 76, and upper shock link 82), and pivot axis 75 b isshared by three members (upper shock link 82, lower shock link 84, andshock absorber 26). In other embodiments, more or fewer pivot axes maybe shared by more than two members, and/or a different combination ofpivot axes may be shared. For example, in some embodiments, the firstend 26 a of the shock absorber 26 may be pivotally supported at pivotaxis 72 b (as shown in FIG. 6A), thus leading to pivot axis 72 b beingshared by three members (main frame 14, link member 74, and shockabsorber 26). If such a design is incorporated into the embodiment ofFIGS. 1-5, the subframe 16 and shock absorber 26 assembly would thencomprise four shared pivot axes. Such a design may raise the center ofgravity of the bicycle as compared to the embodiment shown in FIGS. 1-5,but may also have benefits, such as reduced overall weight, easierand/or cheaper manufacturability, and/or the like. In some embodiments,the pivot axis 72 b may be lower than the design shown in FIGS. 1-5, andthus moving the first end 26 a of the shock absorber to share pivot axis72 b may not raise the center of gravity as compared to the embodimentshown in FIGS. 1-5 (or may not raise the center of gravity as much as ifthe pivot axis 72 b were not lowered). FIGS. 6B and 6C, discussed above,illustrate example embodiments having two shared pivot axes, instead ofthree shared pivot axes.

Sharing of pivot axes by more than two members can have multiplebenefits. For example, each pivot axis requires at least some associatedhardware, such as bolts, axles, bearings, bushings, and/or the like. Bysharing a pivot axis with three or more members, the associated hardwarerequirements may be reduced, thus reducing weight and/or cost, andpotentially increasing manufacturability. For example, in someembodiments, a shared pivot axis may comprise a single axle having aplurality of bearings coupled thereto (for example, at least one bearingper member that is pivotally coupled to the axle). In some embodiments,the axle may be affixed to and/or formed as a part of one of the membersforming that shared pivot axis.

Sharing of pivot axes may also lead to another benefit related toincreased manufacturability and/or reduced manufacturing costs. To havean articulating suspension assembly operate effectively, certaintolerances need to be met. Examples of such tolerances are the tolerancein spacing between pivot axes, and the tolerance in parallel alignmentof the pivot axes. The more pivot axes there are, the more importanttolerance stackups can become, potentially leading to more variation inlocation and/or alignment of the various pivot axes to one another.Accordingly, as the number of pivot axes increases, more precise and/orexpensive methods of manufacturing may be required to maintain thosecharacteristics within design tolerance limits. By sharing pivot axeswith multiple members, however, the overall number of pivot axesrequired in the design can be reduced, and some of the tolerance stackupassociated with additional pivot axes may be eliminated.

Preferably, the pivot axes 72 a and 72 b are both defined by the bottombracket support member 56. As described above, desirably the bottombracket support member 56 is constructed of a monolithic, forged pieceof material. Accordingly, the bottom bracket support member 56 may takeon a more complex structure than the typical welded together tubes of aconventional bicycle frame. Advantageously, the monolithic bottombracket support member 56 can be configured to handle the specific loadsplaced on the main frame 14 by the subframe 16 with a minimum ofmaterial, thereby resulting in a lower overall weight of the bicycleframe 12. Further, the first end 26 a of the shock absorber 26 can besupported by bracket 57 and/or gusset 58, each of which may be attachedto or formed as part of the bottom bracket support member 56. Due to thehigh strength of the bottom bracket support member 56, the seat tube 60and top tube 52 do not have to support the loads placed on the mainframe 14 by the subframe 16 and, therefore, can be lighter in weight.Further, with bracket 57 and/or gusset 58 attached to or formed as partof the bottom bracket support member 56, the down tube 54 does not haveto support the entire load applied by the shock absorber 26 to thebracket 57.

Another benefit of designs disclosed herein is that the rear wheel pathand the shock absorber leverage ratio can be at least partiallyindependent from one another, and thus both optimized. Preferably, theseat stay member 76 supports the rear wheel 24 (shown in FIG. 1) forrotation about hub axis A_(H) and, preferably, the hub axis A_(H) ispositioned above the pivot axis 72 d defined by the lower end 76 b ofthe seat stay member 76 and the rearward end 70 b of the chain staymember 70. Accordingly, the suspension path of the hub axis A_(H) isdetermined primarily by the relative lengths and angles of the linkmember 74, seat stay member 76, and chain stay 70. Desirably, the hubaxis A_(H) moves through a generally vertical wheel path in order toinhibit pedal forces or braking forces from influencing movement of therear wheel 24 throughout the suspension travel path. However, inalternative arrangements, the hub axis A_(H) may move through a morecomplex, curvilinear wheel path. As described above, the illustratedbicycle frame 12 is well adapted to provide a relatively large amount ofrear wheel 24 suspension travel. Preferably, the frame 12 provides atleast about 6 inches of vertical movement of the hub axis A_(H) relativeto the main frame 14 and, more specifically, relative to the surface Supon which the bicycle 10 is being ridden. More preferably, the hub axisA_(H) is configured for at least about 8 inches of vertical movement. Aswill be readily appreciated by one of skill in the art, the movement ofthe hub axis A_(H) is dependent on the overall position of the bicycle10 and, therefore, may not necessarily be vertical. Herein, the term“vertical” is used in reference to the position of the bicycle 10illustrated in FIG. 1. The “vertical” movement of the hub axis A_(H) mayalso be described as movement substantially normal to the surface S.

Furthermore, in the illustrated bicycle frame 12, the rear shockabsorber 26 is actuated by the shock support assembly 80, includingupper and lower shock links 82, 84. Thus, with the preferred arrangementillustrated herein, leverage ratio on the shock absorber 26 isdetermined primarily by the shock support assembly 80, while the wheelpath is primarily determined by the link member 74, seat stay 76, andchain stay 70. Accordingly, each of the leverage ratio and the wheelpath characteristics may be optimized.

In some embodiments, configuration of the shock support assembly 80 andshock absorber 26 may be further optimized by adding a shock extensionto the rear end 26 b of the shock absorber. An example of such anembodiment is shown in FIG. 6D. FIG. 6D shows an example suspensionassembly similar to the suspension assembly shown in FIG. 2, except thata shock extension 31 is attached to the rear end 26 b of the shockabsorber 26. The shock extension 31 may comprise, for example, a firstend connected to a portion of the rear end 26 b of the shock absorber26, and a second end comprising a pair of extension arms pivotallysupported at pivot axis 75 b. Using a shock extension 31 can havevarious benefits, such as changing the shock leverage ratio, avoidinginterference with the rear wheel or seat post, and/or the like.

With reference to FIG. 2, in the relaxed configuration of thesuspension, pivot axis 72 b is preferably above and behind pivot axis 72a. Pivot axis 72 c is preferably also above and behind pivot axis 72 b.Pivot axis 72 d is preferably below and behind pivot axes 72 a, 72 b,and 72 c. Pivot axis 75 a is preferably forward of pivot axes 72 a and72 b, below pivot axis 72 b, and above pivot axis 72 a. Pivot axis 75 bis preferably rearward of pivot axes 72 a and 72 b, forward of pivotaxes 72 c and 72 d, below pivot axes 72 b and 72 c, and above pivot axes72 a and 72 d. Various other embodiments may position one or more ofthese pivot axes differently; however, the present arrangement of pivotaxes has been found to advantageously isolate pedal induced and brakeinduced forces from being transmitted to the rear suspension of thebicycle 10, while also allowing for a more vertical rear wheel traveland a more progressive leverage ratio. As such, these relative pivotlocations are preferred locations.

Alternatively, other relative pivot locations may be used. For example,pivot axis 72 b may be forward of pivot axis 72 a, pivot axis 75 b maybe below pivot axis 72 a, pivot axis 75 b may be rearward of pivot axis72 c, and/or the like. In addition, other modifications apparent to oneof skill in the art may also be incorporated.

Desirably, one or more bearing assemblies are provided at each pivot 72,75 to permit smooth pivoting motion of the rear suspension.Alternatively, bushings or other suitable constructions may also beused, as may be determined by one of skill in the art.

Preferably, the shock absorber 26 is mounted to the bicycle frame 12such that a main body portion of the shock absorber 26 is positionedsubstantially within a perimeter defined in a generally vertical planeby the lower shock link 84, upper shock link 82, link member 74, a linedrawn between pivot axes 72 b and 75 a, and a portion of the main frame14 between pivot axes 75 a and 72 a. With such an arrangement, the shockabsorber 26 advantageously lowers the center of gravity of the bicycle10 and is protected from damage by the lower arm 70, link member 74,down tube 54, and bottom bracket support member 56. In some embodiments,the shock absorber may comprise a reservoir portion, which may also bepositioned within the above-described perimeter, or may be positioned atleast partially outside of the above-described perimeter.

Various modifications to the implementations described in thisdisclosure may be readily apparent to those skilled in the art, and thegeneric principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the claims are not intended to be limited to theimplementations shown herein, but are to be accorded the widest scopeconsistent with this disclosure, the principles and the novel featuresdisclosed herein. Additionally, as further discussed above, a personhaving ordinary skill in the art will readily appreciate, the terms“upper” and “lower” are sometimes used for ease of describing thefigures, and indicate relative positions corresponding to theorientation of the figure on a properly oriented page, and may notreflect the proper orientation of the device as implemented.

Certain features that are described in this specification in the contextof separate implementations also can be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation also can be implemented inmultiple implementations separately or in any suitable sub combination.Moreover, although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to a subcombination or variation of a sub combination.

In describing the present technology, the following terminology may havebeen used: The singular forms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to an item includes reference to one or more items.The term “ones” refers to one, two, or more, and generally applies tothe selection of some or all of a quantity. The term “plurality” refersto two or more of an item. The term “about” means quantities,dimensions, sizes, formulations, parameters, shapes and othercharacteristics need not be exact, but may be approximated and/or largeror smaller, as desired, reflecting acceptable tolerances, conversionfactors, rounding off, measurement error and the like and other factorsknown to those of skill in the art. The term “substantially” means thatthe recited characteristic, parameter, or value need not be achievedexactly, but that deviations or variations, including for example,tolerances, measurement error, measurement accuracy limitations andother factors known to those of skill in the art, may occur in amountsthat do not preclude the effect the characteristic was intended toprovide. Numerical data may be expressed or presented herein in a rangeformat. It is to be understood that such a range format is used merelyfor convenience and brevity and thus should be interpreted flexibly toinclude not only the numerical values explicitly recited as the limitsof the range, but also interpreted to include all of the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. As an illustration,a numerical range of “about 1 to 5” should be interpreted to include notonly the explicitly recited values of about 1 to about 5, but alsoinclude individual values and sub-ranges within the indicated range.Thus, included in this numerical range are individual values such as 2,3, and 4 and sub-ranges such as 1-3, 2-4 and 3-5, etc. This sameprinciple applies to ranges reciting only one numerical value (e.g.,“greater than about 1”) and should apply regardless of the breadth ofthe range or the characteristics being described. A plurality of itemsmay be presented in a common list for convenience. However, these listsshould be construed as though each member of the list is individuallyidentified as a separate and unique member. Thus, no individual memberof such list should be construed as a de facto equivalent of any othermember of the same list solely based on their presentation in a commongroup without indications to the contrary. Furthermore, where the terms“and” and “or” are used in conjunction with a list of items, they are tobe interpreted broadly, in that any one or more of the listed items maybe used alone or in combination with other listed items. The term“alternatively” refers to selection of one of two or more alternatives,and is not intended to limit the selection to only those listedalternatives or to only one of the listed alternatives at a time, unlessthe context clearly indicates otherwise.

What is claimed is:
 1. A bicycle, comprising: a front wheel; a rearwheel; a frame comprising a main frame portion and an articulating frameportion, said articulating frame portion carrying said rear wheel, saidarticulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame link ata third axis; an upper shock link pivotally coupled to the upper framelink and the upper arm at the third axis; and a lower shock linkpivotally coupled to the main frame portion and the lower arm at thefirst axis; and a shock absorber having a first end and a second end,the first end pivotally supported at a fourth axis by the main frameportion, the second end pivotally supported at a fifth axis by the uppershock link and the lower shock link, the shock absorber configured tobias the articulating frame portion to the relaxed configuration.
 2. Thebicycle of claim 1, wherein the fourth axis is collinear with the secondaxis.
 3. The bicycle of claim 1, wherein the upper and lower shock linksare positioned such that the first axis, third axis, and fifth axis arenever coplanar throughout a range of motion of the articulating frameportion from the relaxed configuration to the compressed configuration.4. The bicycle of claim 1, wherein the fourth axis is positioned abovethe fifth axis such that a longitudinal axis of the shock absorberslopes downward from the first end to the second end in all positionsbetween the compressed configuration and the relaxed configuration. 5.The bicycle of claim 1, wherein the fourth axis and the fifth axis areboth positioned below the second axis throughout a range of motion ofthe articulating frame portion from the relaxed configuration to thecompressed configuration.
 6. A bicycle, comprising: a front wheel; arear wheel; a frame comprising a main frame portion and an articulatingframe portion, said articulating frame portion carrying said rear wheel,said articulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame linkand the lower arm; an upper shock link pivotally supported at a thirdaxis by one or both of the upper frame link and the upper arm; and alower shock link pivotally coupled to the main frame portion; a shockabsorber having a first end and a second end, the first end pivotallysupported at a fourth axis by the main frame portion, the second endpivotally supported at a fifth axis by the upper shock link and thelower shock link, the shock absorber configured to bias the articulatingframe portion to the relaxed configuration; and a pedal crank rotatablycoupled to the main frame portion at sixth axis, the first axis beingforward of the sixth axis; wherein, when the bicycle is positioned on ahorizontal surface with the articulating frame portion in the relaxedconfiguration, a horizontal distance from the sixth axis to the firstaxis is at least 1.5 inches.
 7. The bicycle of claim 6, wherein, whenthe bicycle is positioned on a horizontal surface with the articulatingframe portion in the relaxed configuration, the horizontal distance fromthe sixth axis to the first axis is at least 3 inches.
 8. The bicycle ofclaim 6, wherein, when the bicycle is positioned on a horizontal surfacewith the articulating frame portion in the relaxed configuration, ahorizontal distance from a rotational axis of the rear wheel to thefirst axis is no greater than 10 times the horizontal distance from thesixth axis to the first axis.
 9. The bicycle of claim 6, wherein, whenthe bicycle is positioned on a horizontal surface with the articulatingframe portion in the relaxed configuration, a horizontal distance from arotational axis of the rear wheel to the first axis is no greater than 7times the horizontal distance from the sixth axis to the first axis. 10.The bicycle of claim 6, wherein, when the articulating frame portion isin the relaxed configuration, a horizontal distance from a rotationalaxis of the rear wheel to the first axis is at least 18 inches.
 11. Abicycle, comprising: a front wheel; a rear wheel; a frame comprising amain frame portion and an articulating frame portion, said articulatingframe portion carrying said rear wheel, said articulating frame portionhaving a relaxed configuration and a compressed configuration; thearticulating frame portion comprising: a lower arm pivotally supportedat a first axis by the main frame portion; an upper frame link pivotallysupported at a second axis by the main frame portion; an upper armpivotally coupled to the upper frame link and the lower arm; an uppershock link pivotally supported at a third axis by one or both of theupper frame link and the upper arm; and a lower shock link pivotallycoupled to the main frame portion; and a shock absorber having a firstend and a second end, the first end pivotally supported at a fourth axisby the main frame portion, the second end pivotally supported at a fifthaxis by the upper shock link and the lower shock link, the shockabsorber configured to bias the articulating frame portion to therelaxed configuration; wherein the first axis is positioned at least0.50 inches forward of the second axis when the bicycle is positioned ona horizontal surface with the articulating frame portion in the relaxedconfiguration.
 12. The bicycle of claim 11, wherein the upper shock linkis pivotally supported at the third axis by both of the upper frame linkand the upper arm.
 13. The bicycle of claim 11, wherein the rear wheelis rotatably coupled to the upper arm.
 14. The bicycle of claim 11,wherein the lower shock link is pivotally coupled to the main frameportion at a sixth axis, and the upper and lower shock links arepositioned such that the third axis, fifth axis, and sixth axis arenever coplanar throughout a range of motion of the articulating frameportion from the relaxed configuration to the compressed configuration.15. The bicycle of claim 14, wherein the sixth axis is collinear withthe first axis.
 16. The bicycle of claim 11, wherein the fourth axis ispositioned below the second axis.
 17. The bicycle of claim 11, whereinthe second end of the shock absorber comprises a shock extensionpivotally supported at the fifth axis by the upper shock link and thelower shock link.
 18. A bicycle, comprising: a front wheel; a rearwheel; a frame comprising a main frame portion and an articulating frameportion, said articulating frame portion carrying said rear wheel, saidarticulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame linkand the lower arm; an upper shock link pivotally supported at a thirdaxis by one or both of the upper frame link and the upper arm; and alower shock link pivotally coupled to the main frame portion; and ashock absorber having a first end and a second end, the first endpivotally supported at a fourth axis by the main frame portion, thesecond end pivotally supported at a fifth axis by the upper shock linkand the lower shock link, the shock absorber configured to bias thearticulating frame portion to the relaxed configuration; wherein thefirst axis is positioned forward of the second axis when the bicycle ispositioned on a horizontal surface with the articulating frame portionin the relaxed configuration; and wherein the second axis is collinearwith the fourth axis.
 19. A bicycle, comprising: a front wheel; a rearwheel; a frame comprising a main frame portion and an articulating frameportion, said articulating frame portion carrying said rear wheel, saidarticulating frame portion having a relaxed configuration and acompressed configuration; the articulating frame portion comprising: alower arm pivotally supported at a first axis by the main frame portion;an upper frame link pivotally supported at a second axis by the mainframe portion; an upper arm pivotally coupled to the upper frame linkand the lower arm; an upper shock link pivotally supported at a thirdaxis by one or both of the upper frame link and the upper arm; and alower shock link pivotally coupled to the main frame portion; and ashock absorber having a first end and a second end, the first endpivotally supported at a fourth axis by the main frame portion, thesecond end pivotally supported at a fifth axis by the upper shock linkand the lower shock link, the shock absorber configured to bias thearticulating frame portion to the relaxed configuration; wherein thefirst axis is positioned forward of the second axis when the bicycle ispositioned on a horizontal surface with the articulating frame portionin the relaxed configuration; and wherein the fourth axis is positionedabove the fifth axis such that a longitudinal axis of the shock absorberslopes downward from the first end to the second end in all positionsbetween the compressed configuration and the relaxed configuration. 20.A bicycle, comprising: a front wheel; a rear wheel; a frame comprising amain frame portion and an articulating frame portion, said articulatingframe portion carrying said rear wheel, said articulating frame portionhaving a relaxed configuration and a compressed configuration; thearticulating frame portion comprising: a lower arm pivotally supportedat a first axis by the main frame portion; an upper frame link pivotallysupported at a second axis by the main frame portion; an upper armpivotally coupled to the upper frame link and the lower arm; an uppershock link pivotally supported at a third axis by one or both of theupper frame link and the upper arm; and a lower shock link pivotallycoupled to the main frame portion; and a shock absorber having a firstend and a second end, the first end pivotally supported at a fourth axisby the main frame portion, the second end pivotally supported at a fifthaxis by the upper shock link and the lower shock link, the shockabsorber configured to bias the articulating frame portion to therelaxed configuration; wherein the first axis is positioned forward ofthe second axis when the bicycle is positioned on a horizontal surfacewith the articulating frame portion in the relaxed configuration; andwherein the fourth axis and the fifth axis are both positioned below thesecond axis throughout a range of motion of the articulating frameportion from the relaxed configuration to the compressed configuration.